Repeated action injector apparatus



- T. J. LORD ETAL REPEATED ACTION INJECTOR APPARATUS May 12, 1959 2 Sheets-Sheet 1 Fild Oct. 24, 1956 mww sm w INVENTORJ Thmzxii. corp and May 12, 1959 -r. JJLORD ET AL REPEATED ACTION INJECTOR APPARATUS ZSheetS-Sheefc 2 Filed Oct. 24, 1956 fl rATTORNEY United States Patent REPEATED ACTION INJECTOR APPARATUS Thomas J. Lord, Middletown, and Gerrald G. Foltz, Dayton, Ohio, assignors to United Aircraft Products, Inc., Dayton, Ohio, a corporation of Ohio Application October 24, 1956, Serial No. 617,979

7 Claims. (Cl. 251-13) This invention relates to repeated action injector apparatus, especially as used in fuel systems to inject repeated quantities of fuel into a burner until ignition occurs.

An object of the invention is to produce an electrically controlled device operable to deliver constant pre-determined quantities of fuel during each cycle of operation.

Another object of the invention is to limit the injector device to a pre-determined number of injections or pulses in any one series of operations.

A further object of the invention is to obviate a continuous supply of fuel to the burner as may result from a failure of electro-magnetic valve means constituting the shut off to the burner.

Still another object of the invention is to discontinue the supply of fuel to the burner in the event that ignition takes place therein prior to completion of the pre-determined number of pulses or injections of the injector device.

Other objects and structural details of the invention will appear more clearly from the following description when read in connection with the accompanying drawings, wherein:

Fig. 1 is a view in side elevation, partly broken away, of an injector device in accordance with the illustrated embodiment of the invention;

Fig. 2 is a detail view, enlarged with respect to Fig. l, of an orifice mechanism in the injector device;

Fig. 3 is a view in cross-section, taken substantially along the line 3-3 of Fig. 1;

Fig. 4 is an electrical diagram showing the control system for theinjector device;

Fig. 5 is a detail view, enlarged with respect to Fig. 2, showing in front elevation an orifice disk therein; and

Fig. 6 is a diagrammatic view of a rotary solenoid assembly comprised in the electrical controls for the injector device.

Referring to the drawings, an injector device in accord ance with the illustrated embodiment of the invention is adapted to be interposed in a line flowing fluid under pressure, as for example in the fuel inlet line to the after burner in a turbojet engine. In this system, it is desired to inject pre-determined quantities of fuel into the after burner chamber in successive pulses, which are continued until ignition occurs or until a pre-determined number of pulses have been completed.

As shown, the injector device comprises a body 10 having longitudinal bores 11 and '12. The former opens into a recess 13 over-lying the bore 12 and separated therefrom by a wall 14. The chamber 13 and bore 12 are connected by a port 15 in which is installed a bushing 16 providing at its upper end a seat for a valve stem 17 on the plunger 18 of an electro-magnetic device 19. The valve stem 17 tends normally to engage the seat on bushing 16, by virtue of a compression spring 21. .Upon energizing of the coil 22 of the device 19, however, the plunger 18 is retracted or moved vertically upward whereby to unseat the valve stem 17. It .will be understood that communication bepipe 23 for conducting fluid away from the injector device, as to the after burner. Toward the opposite end of the body 10, the bore 11 opens into a counter-bore 24 in which is installed a bushing 25, a flange on one end of the bushing seating in a bore 26. Still further, toward the a other end of the body 10, the bore 26 is expanded and internally threaded to receive a tubular housing member 27 The latter is open at its outer end to receive a pipe 23a by which fuel is supplied to the injector device, the device being in effect installed or interposed in a pipe line 23--23a.

Intermediate its ends, the body 10 extends upward to define with a closure plate 28 a compartment 29 in which is a micro-switch 31 controlling the energizing and deenergizing of coil 22 of electro-magnetic device 19. A switch plunger 32 is arranged to be actuated by a lever 33 pivotally mounted on a stud 34 and having an end portion extending downward into the bore 26 in a path at right angles to the longitudinal axis thereof. With the parts positioned as illustrated the switch 31 may be considered closed with respect to the coil 22 so that the valve plunger 17-18 is at this time lifted, opening flow through the injector device. A rocking of the lever 33 in a clockwise direction releases the plunger 32, enabling the switch 31 to open the circuit through the coil 22 whereupon the plunger valve 1718 is permitted to drop to a seat on bushing 16, so closing the flow path to the outlet pipe 23.

That end of switch actuating lever 33 which extends into the bore 26 is disposed to the front of or beyond one end of a cylinder 35 longitudinally disposed in the housing 27. An enlarged end portion 36 on the cylinder 35 is received ina counterbore 37 in the bore 26. The cylinder is thus fixed in a concentric relation with the bore 26 and with the housing 27, with the major part of the length of the cylinder spaced from the housing in a manner to define an annular passageway .38 in surrounding relation to the cylinder.

The outer end of the cylinder35, or that end facing the inlet end of the housing 27, is closed by an orifice mounting head 39 stationar-ily installed therein. The latter is spaced from adjacent portions of the housing 27 so that incoming liquid from the pipe 23a may flow freely to the annular passage 38 and then by way of a longitudinal port 41 in the enlarged portion 36 to bore 26, bores 11 and 12 and outlet pipe 23. I s

The closure head 39 is formed with a longitudinal through bore 42 and a counter-bore 43. The latter isdisc is pressed against the plate. It will be apparent that the construction and arrangement of parts is such as to provide for a metered flow of fluid through the bore 42 in either direction. Thus, the fluid flow in a leftward direction through the bore presses orifice disc 49 against the plate 46. The fluid accordingly flows past the seat 52,

around the disc 49 and through the openings 47 where it presses the disc 48 against the seat 51. Flow past the disc 48 accordingly is prevented except that which may take place through the small diameter orifice 4811 (see Fig. 5 at-the center of the disc.

In the event of fluid flow in a reverse direction, that is toward the right as viewed in Fig. 2, the orifice disc 49 is effective to control the rate of flow through the bore 42, the disc 48 being at this time ofi its seat 51 and pressed against the. plate 46.

Intermediate the closure head 39 and the opposite end of the cylinder 35 is a piston 55 received in the cylinder for longitudinal sliding motion therein. A spring 56 is interposed in the cylinder between the piston and the partly closed inner end of cylinder 35 in a manner to maintain the piston normally in a retracted position as shown wherein it limits against the closure head 39. Attached to the piston 55 and extending through and beyond the inner end of the cylinder 35 is a rod v57. Intermediate its ends, the rod 57 is formed with a reduced diameter portion 58 which is embraced by the downwardly extending end of the switch actuating lever 33, the latter being forked at such lower end, as indicated in Fig. 3. The reduced diameter portion 58 of the rod 57 defines thereon longitudinally spaced apart shoulders which, it will be understood, are brought alternately into cooperative relationship with the switch actuating lever 33 as the piston 55 reaches relatively extended and retracted positions. Thus, in the illustrated instance, a retracting motion of the piston has caused the end of the rod 57 to engage lever 33 and rock it in a counterclockwise direction depressing plunger 32 with the result previously noted. In a predetermined position of extension of the piston 55, an intermediate shoulder on rod 57, at the opposite end of reduced diameter portion 58, engages the lever 33 and rocks it in an opposite or clockwise direction, releasing the plunger 32. The outer end of the rod 57 is formed as a valve 59 and is adapted to seat on the bushing 25 to close off flow to the bore 11 and outlet 12.

Assuming the fuel pumps or other pressure generating means to be operating, and further assuming the valve plunger 17--18 to be closed, all portions of the device directly communicating with the inlet end thereof are filled with fuel under pressure. The piston 55 accordingly is under control of the spring 56 and occupies a retracted position in the cylinder 35. The lever 33 is in a counterclockwise position of adjustment, with plunger 32 depressed. In this position of the parts, as will here- 'inafter more clearly appear, the solenoid 22 tends to become energized, and, if'electrical energy now is turned on or supplied to the device, the solenoid coil will become energized and will retract the plunger 18, opening the device to fuel flow from the inlet and to the outlet end thereof.

The area of the annular passage 38 is greater than the area of the opening 41. The result is that a pressure difference is established on opposite sides of the opening 41, such difference being thus also applied across the as sembly comprising closure head 39 and piston 55. Flow through the orifice plate assembly 45 accordingly results and inward motion of the piston 55 thereby is effected. The pressure difference established across the opening 41 is accordingly utilized as a force to effect motion of the piston 55 inward in the cylinder 35 against the resistance of the spring 56. The pressure difference obtained is related to the rate of flow through the passage 38 and will be of sufiicient magnitude to overcome the spring 56.

The piston 55 will move inward in the cylinder at a rate determined by the rate of flow through the orifice disc 48, and this may be considered roughly to be a function of the area of the orifice multiplied by the amount of pressure difference set up by the opening 41. The arrangement is such as to produce a constant ratio between the movement of the piston 55 and the rate of flow through passage 38 whereby for any given travel of the piston a constant pre-determined volume of fuel will have passed through the passage 38 and out of the device.

The piston 55 begins to move immediately that valve plunger 18 is lifted and continues until the intermediate shoulder on rod 57 engages and shifts lever 33 in a clockwise direction to release the plunger 32. When this occurs, the circuit to solenoid coil 22 is open. Plunger 18 descends and shuts off flow through the bushing 16 to the outlet pipe 23. The liquid pressures up stream and down stream of the opening 41 are thus permitted to equalize, and the piston 55 is restored to control of the spring 56 Which returns the piston from extended toward retracted position in the cylinder. As the piston reaches fully retracted position the outer end of rod 37 engages and rocks the lever 33 to a counterclockwise position of adjustment, tending to reclose the circuit throughcoil 22. Another cycle of operation of the injector device is so initiated, and, so long as the electrical control circuit remains unbroken, the device will automatically go through repeated cycles, in effect ejecting each cycle a pre-determined quantity of fuel.

It may be considered that the fuel entering the inlet end of the device is divided into a primary stream which goes by way of passage 38, opening 41 and bores 11 and 12 to the outlet, and a secondary stream which goes through the orifice plate assembly for the operation of piston 55. As noted there is a pre-determined constant ratio flow between these streams which is, of course, variable by substituting other orifice plate assemblies.

The closing of flow through the injector device through the engagement of valve 59 with bushing 25 occurs only upon failure of the electrical system. Thus, the parts are so constructed and arranged that the adjustment of the lever 33 to a clockwise position to de-energize coil 22 is pre-determined to occur when the valve end 59 of the rod 57 reaches an extended position approximately as indicated in broken lines in Fig. 1. There is accordingly normally no shutting off of flow through the device as a function of engagement of the valve end 59 with the bushing 25. Should the electrical system fail to operate, however, and the valve plunger 17-18 fail to shut ofi flow when the parts reach the indicated position, the continued extending motion of the piston 55 will cause the valve 59 to seat upon the bushing 25 thereby interrupting further flow through the unit. A spring 60 may be attached to the lever 33 to return the lever from such induced overtravel movement.

Further" in accordance with the present invention,-the injector device is made a part of an electrical control system by which the cycles of operation of the device may be limited to a pre-determined number in any one series, and by which the injections or pulses of the device may be discontinued at any point in the series when ignition occurs and irrespective of whether the pre-determlned number of cycles or pulses has been completed.

As shown in Fig. 4, a main power conductor 61 has-interposed therein a main control switch 62, normally open. The conductor 61 is connected by a lead 63 to one of a series of electrically conductive segments 64 on a stationary contactor ring 65. Also, the conductor 61 is connected by a lead 66 with one of a series of electrically conductive segments 67 on the ring 65 in alternating relation to the segments 64 and insulated therefrom. A rotor 68 selectively interconnects the segments on the ring 65, the contactor ring, the rotor and the means for rotating the rotor constituting a stepping switch assembly. The rotor is advanced, in a practical embodiment of the invention, by a rotary solenoid, herein represented by the coil 69, the rotary solenoid advancing the rotor 68 through a ratchet mechanism one step for each complete opera tion of the solenoid. Standing normally in what may be termed a home position, the parts of the rotor 68 interconnect the several segments 67 on the ring. A first increment of rotary movement of the rotor, effected by a first complete actuation of the solenoid 69, moves the rotor until each part thereof is in contact with a respective segment 64 at the number one position thereof. A second increment of movement advances the rotor to the number two position, a third increment to the number three position and a fourth increment returns the rotor to its starting or neutral position. The instant stepping switch assembly is constructed and arranged to obtain three pulses of the injector device upon closing of the main control switch 62 and then to discontinue operation of the device.

Another of the segments 67 of the stepping switch assembly is connected by a lead 71 through the coil 69 to ground. Another of the segments 64 is connected by a lead'72 to a switch arm 73 forming a part of the previously described switch device 31 in the injector unit. The switch arm 73 is designed alternately to contact a terminal 74 and a terminal 75 under control of the lever 33 and piston 55. The terminal 75 is connected by a conductor 76 to a switch' arm 77 of a second control switch mechanism alternately in contact with a terminal 78 and a terminal 79. The terminal 78 is connected to ground by way of conductor 81, passing through the coil 22 and joining lead 71. The terminal 79 is connected by a lead 82 with a terminal 83. The latter is connected through a switch arm 84 with a conductor 85 leading to the terminal 74 of switch device 31 and connected also by way of lead 86 with the lead 71 in advance of the solenoid 69.

The switch arm 84 is adapted to be rocked by a cam 87 out of engagement with terminal 83 once upon each complete actuation of the solenoid 69', the cam being connected to the solenoid to move to and fro through a sufficient arc to effect the desired disengagement and reengagement of the switch arm 84 and terminal 83 once for each cycle of operation of the solenoid.

When the switch 62 is closed to initiate after burning, current flows into the one segment 64 by way of lead 63 but there is at present no further connection from this segment into the system. Current flows also by way of lead 66 into the one segment 67 and thence through rotor 68 to the lead 71 and from there to ground. The solenoid 69 is accordingly energized, and advances the rotor 68 out of its neutral position to the number one position on the segments 64. At the same time, the solenoid 69 is permitted to become de-energized and is restored to a starting position. A circuit now is closed through a pair of the segments 64, conductor 72 and switch arm 73 to terminal 75 and thence backto ground by way of the solenoid 22 which accordingly becomes energized, opening the injector device for flow therethrough. As the piston 55 reaches its pre-determined extended position under the displacing influence of fuel flow, the switch arm 73 is shifted into contact with the terminal 74. The coil 22 is thus removed from the circuit and solenoid 69 substituted therein, by way of lead 86, so that the stepping switch assembly is reactuated while the solenoid coil 22 remains de-energized. The stepping switch is accordingly advanced to its number two position. In the meantime piston 55 is retracting in the injector device and as it reaches fully retracted position effects a return of switch arm 73 back to engagement with terminal 75. Solenoid 69 is thus de-energized and restores itself to a starting position while coil 22 is re-energized and the passages through the injector device are again opened for flow therethrough. This cycle repeats itself through the number three position of the stepping switch and the parts returned finally to the home position illustrated.

The switch arm 77 and terminals 78 and 79 may be considered to be a part of an automatic switch device responding to a condition changing as a result of ignition in the after burner. This may be temperature since temperature within the after burner chamber mounts rapidly upon ignition. It may also bepressure taken from the turbine since the changed speed of rotation resulting from ignition in the after burner affects the developed pressure at the turbine. The parts are constructed and arranged so that the switch arm 77 normally engages the terminal 78 but in response to the changing condition mentioned 6. will move from terminal 78 to terminal 79. The result of this is to connect terminal 75 of the switch 31 to the lead 82 and oscillating switch arm 84. At the same time, the coil 22 is removed from the circuit. The result is that the solenoid 69 is energized and de-energized once for each complete movement of the cam 87. Thus, after ignition in the after burner the cam 87 will be effective to advance the stepping switch such additional steps as may be required to return it to its home or starting position.

The arrival of the stepping switch in home position finds the coil 69 energized, which energization is continued by reason of the electrical connection efiected through lead 66, segments 67, rotor 68 and lead 71. The actuating solenoid of the stepping switch accordingly is in effect stalled and unable to complete its return motion. No further operation of the injector device thus can take place until the switch 62 is opened and then reclosed.

As indicated in Fig. 4, the elements 64 through 69 and cam 87 form a part of an integrated unit. This unit is a commercially known and available solenoid assembly, shown in diagrammatic form in Fig. 6. As there shown, the solenoid is of the rotary type wherein the coil 69 is mounted on a bushing 88 and contained within a stationary housing 89. A shaft 91 is rotatably mounted in the bushing 88 and extends through and beyond the housing 89 at its opposite ends. On one end of the shaft 91 is a plate 92 having one or a plurality of wedge shaped cam surfaces 93 on the side adjacent to the housing 89. In the adjacent surface of the housing 89 is a pocket 94 to receive a ball 95 adapted to ride on the cam surface 93 as an inclined plane. On the opposite projecting end of the shaft 91 is a ratchet 96 adapted to engage a complementary ratchet portion 97 on one end of a shaft 98 mounting the rotor 68 and cam 87. In accordance with the known mode of operation of devices of this kind the energizing of coil 69 serves to retract the shaft 91 in a direction to engage the ratchet portions 96 and 97. This motion brings the cam surface to bear upon the ball 95 and as retracting motion of the shaft continues the ball in elfect rides up the surface of the cam 93, the forces involved being resolved into a rotary motion of the plate 92 and its shaft 91 in conjunction with the axial movement thereof. Accordingly. the energizing of the coil 69 is effective to transmit a rotary impulse to the shaft 98 for a stepping motion of the rotor 68 as has been described. Suitable spring means return the shaft 91 and plate 92 to normal position upon the de-energizing of the coil 69.

What is claimed is:

1. An injector device of the class described, comprising a housing to be interposed in a line flowing liquid under pressure and presenting an inlet and an outlet, a passage in said housing extending between said inlet and said outlet, said passage providing at an intermediate point therein a valve seat, means for alternatively opening and closing said passage to flow therethrough, including a control device having alternative positions of adjustment, piston means for actuating said control device spring urged to a retracted position, said piston means setting said control device to one position of adjustment only as it reaches a retracted position and to the other position of .adjustment only as it reaches an extended position, means for diverting a portion of the liquid from said passage to said piston means, means creating a pressure drop in said passage to extend said piston means from retracted position, and a valve on said piston means seating on said valve seat in response to over travel of said piston means beyond said extended position whereby positively to cut off flow through said passage in the event of failure of said control device.

2. An injector device of the character described, comprising ahousing to be interposed in a line flowing liquid under pressure, a valve in said housing adjustable to open and closed positions, in the latter of which flow through said housing is shut off, a control device for said valve having alternative positions of adjustment in a first one of which said valve is open and in a second one of which said valve is closed, a piston in said housing displaceable under the influence of the liquid flow from a retracted position to an extended position, a spring for returning said piston from extended to retracted position in the absence of liquid flow, a connection between said piston and said control device effective only as said piston reaches said extended position and said retracted position for setting said control device to said alternative positions of adjustment, said connection including resilient means yielding to an over travel of said piston beyond said extended position, and valve means for shutting off flow through said housing in response to over travel of said piston as described.

3. An injector device according to claim 2, characterized in that said valve means comprises a valve seat in the path of flow through said housing and a valve on said piston engageable with said seat in response to over travel of said piston beyond said extended position.

4. Injector apparatus of the class described, including electro-magnetic valve means adapted to be interposed in a line flowing fluid under pressure and operable to permit and to deny flow therethrough, an electrical circuit for controlling the energizing and de-energizing of said means including a power source, a rotary stepping switch, electro magnetic means advancing said switch in stepby-step fashion in response to the energizing and deenergizing thereof, power conducting means including connections from said source through said stepping switch to said electro magnetic valve means and to said electro magnetic means, a control switch settable to a first position in which the power from said stepping switch is used to energize said electro magnetic valve means and to a second position in which said power is used to energize said electro magnetic means, a piston displaceable by flowing fluid in said line to an extended position,

in which said control switch is moved thereby from its said first position to its said second position, and a spring for returning said piston to a retracted position in which said control switch is moved from its said second position to its said first position.

5. Injector apparatus according to claim 4, characterized in that said stepping switch has a neutral position in which said power source is connected to said electro magnetic means and a series of positions of predetermined number in which said power source is connected to said control switch.

6. Injector apparatus of the kind described, including electro-magnetic valve means adapted to be interposed in a line flowing fluid under pressure and operable to deny flow therethrough when de-energized, and electrical circuit for controlling the energizing and de-energizing of said means including a power source, a rotary stepping switch having a plurality of series of operating positions and intervening neutral positions, electro-magnetic means advancing said switch through successive positions in response to the energizing and dc-energizing thereof, a power conductor from said source to said stepping switch, said switch in a said neutral position connecting said source to said electro magnetic means for energizing thereof, power conductor means from the operating positions of said stepping switch to said electro-magnetic means and to said electro-magnetic valve means, a control switch in said conductor means settable to a first position connecting the operating positions of said stepping switch to said electro-magnetic valve means and settable to a second position connecting the operating positions of said stepping switch to said electro-magnetic means, and a device responding to volume flow through said line alternately to shift said control switch between its said first and second positions.

7. Injector apparatus according to claim 6, characterized by another control switch settable to open the circuit to said electro-magnetic valve means for deenergizing thereof and to close a supplemental circuit from the operating posit-ions of said stepping switch to said electro-magnetic means, and means actuated by said electro-magnetic means for intermittently opening and closing said supplemental circuit.

References Cited in the file of this patent UNITED STATES PATENTS 2,443,648 Austin et a1. June 22, 1948 2,736,166 Mock Feb. 28, 1956 2,745,625 Booth May 15, 1956 FOREIGN PATENTS 706,060 Great Britain Mar. 24, 1954 

